1. Field of the Invention
The teachings provided herein are generally directed to a safe and efficient cutting head for removing a target tissue from a subject during a surgical procedure.
2. Description of the Related Art
Intervertebral disc disease is a major worldwide health problem. In the United States alone almost 700,000 spine procedures are performed each year and the total cost of treatment of back pain exceeds $30 billion. Age related changes in the disc include diminished water content in the nucleus and increased collagen content by the 4.sup.th decade of life. Loss of water binding by the nucleus results in more compressive loading of the annulus. This renders the annulus more susceptible to delamination and damage. Damage to the annulus, in turn, accelerates disc degeneration and degeneration of surrounding tissues such as the facet joints.
The two most common spinal surgical procedures performed are discectomy and spinal fusion. These procedures only address the symptom of lower back pain, nerve compression, instability and deformity. The objective of the spinal disc fusion procedure is to restore, maintain and stabilize disc height, and/or reduce back pain. The procedure is generally performed by removing central disc material such and inner annulus, nucleus pulposus and the cartilage on the endplates before replacing with bone graft and a scaffold to effect fusion of the vertebral bodies within the treated disc for height stabilization. This removal process is called a discectomy and is both tedious and frequently inadequate which can result in compromised fusion, as well as traumatic and time consuming due to the large incision and dissections required to expose the disc for discectomy.
In a typical discectomy procedure, a nucleotomy is first performed in which the nucleus is loosened by using a curette or a manual shaver to shear the nucleus loose and then removed using a rigid grasper called a rongeur. The surgeon has to insert the rongeur through an opening in the disc called an anulotomy, grasp nucleus and remove out of the disc and the surgical access, clean the jaws and reinsert for more grasping of disc repeatedly. This process can pose safety issues for tissues in between tool passage such as nerves. Furthermore, disc debris left behind can hinder efficient subsequent tissue removal and insertion of the discectomy tools into the disc. The second step is decortication in which cartilage attached to the bone (cartilaginous endplate) is removed by the use of rigid scrapers such as a curette or a rasp to help promote a strong intervertebral fusion. Peeled cartilage are removed by scooping with a curette and withdrawn out of the body by the use of a rongeur. Tissue debris left behind can also compromise efficiency and effectiveness of the decortication resulting in a weaker fusion. Moreover, corners inside the discs are often hard to reach by current state-of-the art tools, often leaving additional areas of inadequate disc removal.
In addition, state-of-the-art systems using a combination of suction and cutting suffer clogging problems due to excised tissue becoming lodged in the system. One of skill will appreciate that problems with clogging during a surgical procedure can be problematic, and a solution to such clogging problems is highly desired.
Although several advanced tools have been developed, none have addressed all of these issues adequately. One of skill in the art would certainly appreciate a discectomy system that is (i) less tedious and time consuming to use, (ii) less prone to clogging by excised tissue; (iii) safer to the subject undergoing the surgery, and (iv) more effective in promoting a strong intervertebral fusion.